Primary pulmonary adenocarcinoma in a Labrador retriever dog

A 10 years old Labrador retriever female had history of coughing along with occasionally hemoptysis, laboured breathing, restlessness and exercise intolerance. Radiography revealed extensive areas of pulmonary consolidation along with increased cardiac silhouette. The dog did not respond to treatment and succumbed. On necropsy, almost 90% of the caudal left lobe of lung was effaced and markedly expanded by neoplastic mass. On cutting, the tumorous lung revealed white to grey, firm, multi-lobulated mass with accumulation of mucus. Both the cardiac ventricles were dilated with more severity in right side. On microscopic examination, neoplastic cells of lung were arranged in papillary (predominate pattern), acinar or occasionally micropapillary pattern. High cuboidal to columnar neoplastic cells showed ample eosinophilic cytoplasm and round to oval nuclei. Alveoli were filled with inflammatory cells mixed with mucus. Neoplasm showed multifocal necrosis and hemorrhages. On the basis of gross and histopathology, the neoplasm was diagnosed as primary pulmonary adenocarcinoma.